Questions about Mathematica's date and time functions.

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7
votes
5answers
179 views

How to do DateDifference on table items containing dates

I have a Table with data in form {{date}, value}: ...
7
votes
3answers
151 views

Different results with DateRange and LeapYearsQ in Mathematica 9 and 10

With Mathematica 9.0 for Mac OS X x86 (64-bit) (January 24, 2013) one could use DateRange[{2000}, {2010}, "Year"] to achive ...
1
vote
1answer
77 views

How to get matching starting dates for different `FinancialData` properties? [closed]

Why do the "Return" and "Volume" outputs of FinancialData differ? Consider the following ...
4
votes
1answer
47 views
7
votes
1answer
116 views

Bug in DateListPlot in Mathematica 10

Mentioned this already in an answer to a related question. DateListPlot in Mathematica 10 has a horrible bug: If two points have the same time coordinate, only one is plotted; the others are ignored. ...
6
votes
3answers
284 views

Does Mathematica have Month Range and Day range?

It is known that CharacterRange["a", "z"] gives list of characters from a to z. Does Mathematica have something similar for weekdays and months of the year? ...
1
vote
0answers
22 views

Updating values in a Dataset [duplicate]

I'm starting to work with datasets. They seem like a useful addition to Mathematica. However, there's one fairly major stumbling block I can't get over. How do I update data in a dataset? I have a ...
4
votes
3answers
158 views

How to get a list of days from July 4th to Oct 4th over a range of years

I'd like to create a list with days from the 4th of July to the 4th of October starting in July 1970 to the current date. I tried to use DateRange, but I'm a bit ...
0
votes
1answer
40 views

Export date with specified format

My problem is that I want use PGFplot in $\LaTeX$ to draw my graphs, which x axis is a date. Therefore the output file has to have one column "UTC time" (YYYY-MM-DD hh:mm:ss) and the second one is the ...
3
votes
2answers
96 views

Slow work of TimeSeriesWindow

I have financial data (list of time-values pairs). There are more than 13000 elements. ...
4
votes
1answer
62 views

Poor (network) performance of Interpreter[“Time”]

I was surprised to see that Interpreter requires external WR resources as this is not documented, at least not here. On a 3Ghz iMac, took ~half a minute to ...
1
vote
1answer
106 views

Addition and subtraction of TimeObjects in v10 [closed]

Documentation states that "TimeObject allows addition and subtraction of time quantities". I can see that subtraction is fine, (example from doc page) TimeObject[{16, 17, 21}] - TimeObject[{10, ...
2
votes
1answer
131 views

BarChart that lines up with dates in DateListPlot

I am trying to create a chart similar to the view offered by TradingChart, but with custom data not relating to finance. ...
6
votes
3answers
451 views

Friday the 13th related tables

This code ...
0
votes
1answer
70 views

Extract data from DateListPlot, limited by PlotRange

Extracting the points from a line in a ListPlot in this answer uses points = Cases[Normal@plot, Line[pts_] :> pts, Infinity]; This works in DateListPlot ...
3
votes
3answers
64 views

Alternatives to DateQ of Calendar Package

This answer notes that Calendar package has a function DateQ but the documentation suggests that the input is limited to a fixed ...
-5
votes
1answer
57 views

how to mean of day,month value

data={{{2006, 1, 1, 0, 0, 0.}, 326.492, {2006, 1, 1, 3, 0, 0.}, 323.08, {2006, 1, 1, 6, 0, 0.}, 314.223, {2006, 1, 1, 9, 0, 0.}, 314.361, {2006, 1, 1, 12, 0, 0.}, 322.048, {2006, 1, 1, 15, 0, ...
0
votes
1answer
78 views

Text with date, how to convert?

I use this script to recognise a date in a textfile and write the result in another file. ...
0
votes
2answers
117 views

How to partition three years of data into daily samples

I'm trying to find mean of temperature data list. The temperature data list has 3 hours steps which means I have 365*8=2920 temperature measurements per year. My data are temperatures of 13 years. ...
2
votes
0answers
81 views

DateList does not output the correct time, but Date does

I noticed a strange thing when trying the new astronomical data functions in Mathematica 10 on my Raspberry Pi. The Sunrise and ...
0
votes
2answers
80 views

Convert epoch seconds to date [duplicate]

I have got the following datetime from an API: 1395401384298 I am guessing it is in epoch miliseconds time (it should be one day in 2014) How can i convert it into a more readable String? I have been ...
2
votes
2answers
103 views

Counting Events in a moving date range

I want to count the number of times events take place in a date range. The counting is done over a window of e.g. 28 days where the goal is to have between 11 and 13 events in the time window. The ...
1
vote
2answers
75 views

I'm trying to filter a date range by day of month and day of week - what am I doing wrong?

I am trying to generate a list of dates that match two criteria: they have to all be the first of the month, and they have to be a particular day of the week, Sunday in my case. The code I have ...
1
vote
1answer
148 views

Splitting dates into groups in half year steps

list = DayRange[{1999, 1, 1}, {2014, 2, 6}] I want to split this list into sublists one and a half year long, moving a half year forward every time. That would ...
3
votes
4answers
191 views

Finding the location of the last day of the month in a list of dates

My question differs from earlier questions about getting the eom dates from a list; I want to get the position of those dates so I can get the corresponding values from other lists. My problem seems ...
5
votes
4answers
373 views

How to Merge Date and Time?

Given the following time series data where row is date and column is time intervals. ...
7
votes
1answer
182 views

ScheduledTask with scoped variables. Working with timed evaluation

I guess I have to try harder and focus more but timed evaluation always frustrates me. I will show the issue on simple example of delayed trigger. ...
2
votes
2answers
100 views

Converting a date to a calendar quarter

I have a list that includes dates. I need to convert each date to be the last day of the quarter that it's in. So for example I want {2013,7,1,0,0,0} to become {2013,9,30,0,0,0}. Actually I don't ...
4
votes
2answers
141 views

How to change start and end date of DateListPlot with Manipulate?

Let's say I have a one dimension list d with length L. The $x$-axis in the plot starts from ...
5
votes
1answer
109 views

Why DateDifference returns machine number?

Is there any specific reason why DateDifference cannot give an exact number in this case? ...
5
votes
2answers
123 views

How can AbsoluteTimes be split by date faster?

I have data where the date is stored as an AbsoluteTime. Here's a dummy dataset: ...
4
votes
0answers
83 views

JewishNewYear date limitation

The documentation for the function "JewishNewYear" in the "calendar" package declares that the year argument must be between 1900 and 2100. No explanation is given for this limitation. The function ...
6
votes
2answers
770 views

Measuring execution time of code

How one can measure the execution time (time that is spent for code to finish) of a program in Mathematica? I understand that there are general timing functions (Timing, AbsoluteTiming, TimeUsed, ...
4
votes
1answer
318 views

UNIX time to DateList

I have data that is timestamped with UNIX time, which is the number of seconds since January 1, 1970 UTC. Unfortunately, it seems that most of the date and time functions in Mathematica are based on ...
37
votes
1answer
796 views

How can I manipulate TemporalData?

Version 9 introduced TemporalData but, truth be told, the documentation doesn't suggest that one can do much with it. Many of us have probably assumed we'd be ...
3
votes
4answers
229 views

Test whether date is in a certain period

I have one table which contains time periods ("start" and "end") and a "type" for every ...
3
votes
2answers
186 views

WeatherData for the 15th day of each month

Suppose we have WeatherData["Helsinki", "MeanTemperature", {{2007, 1, 1}, {2012, 12, 31}, "Day"}] How we can have data just for 15th day of each month?
2
votes
1answer
160 views

Importing data from Excel for DateListPlot

I am importing data from Excel and plotting it with DateListPlot. My code is ...
6
votes
6answers
401 views

Sort list by day names (Monday, Tuesday, etc)

I have some dates in a list, and I want to plot how many of those dates are Monday, Tuesday, etc. I'm using this: data = {...} Tally[DayOfWeek /@ data] and I ...
1
vote
4answers
131 views

Data format of Date including data

I have ...
17
votes
1answer
1k views

The Orbit and Perigee of the Flamsteed comet

Historical context This year we have the 330-th anniversary of the Battle of Vienna - one of the great formative events of European history, it took place on September 12, 1683. Kara Mustafa, Grand ...
2
votes
1answer
142 views

ReadList importing negative times

This is probably an easy question to answer, but I need a fresh eye... I'm struggling with processing the following file (extract shown here) It's a list of dates, and positive/negative time durations ...
6
votes
2answers
192 views

How can this AbsoluteTime call be made faster?

I need to convert tons of date strings into absolute times. This generates an example data set of 10,000 strings: ...
4
votes
2answers
236 views

Can Mathematica understand Excel dates when in number format?

I have a very large Excel file with dates in the format 2013/01/17 08:02:00 PM which is a custom date format. I have to convert this file to CSV in order to import it into Mathematica because I can't ...
6
votes
2answers
518 views

Select elements of list within a date range

I have a list which consists of elements each of which has a date in DateList format, a number and a flag (Y/N). e.g. ...
3
votes
3answers
256 views

How to paint part of DateListPlot?

My graph is about fires (burned area) over 12 years presented in one Date List Log Plot. Because most of fires are in summer (as expected) I would like to highlight that with different background ...
7
votes
3answers
307 views

Find all the last weekends in a year

In order to obtain the weekends of a year you'd use something like this: ...
6
votes
5answers
318 views

Handling holidays in financial time series

I have two lists: list1and list2, which are financial time series with only 2 variables—date and price. The problem is: these ...
11
votes
5answers
850 views

Sort date list in format DD/MM/YYYY

I have a list of dates (ranging from 2007 to 2012) in the DD/MM/YYYY format and I need to sort this list. My problem is, when I simply use Sort[] I get: ...
1
vote
1answer
298 views

Converting Excel serial dates with NETLink

Excel serial dates are not straightforward to convert since they include non-existent dates, e.g. {DatePlus[{1990, 1, 0}, 59], DatePlus[{1990, 1, 0}, 60]} ...